Steam-boilers and apparatus to be used on board of steamboats to



June 1, 1915.

DRAWING A careful search has been made this day for the original drawingor a photolithographic copy of the same,

for the purpose of reproducing the said drawing to form a part of thisbook, but at this time nothing can be found from which a reproductioncan be made.

Finis D. Morris,

Chief of Division B.

AWK.

UNITED STATES PATENT OFFICE.

CADWALLADER EVANS, OF PITTSBURGH. PENNSYLVANIA.

STEAM-BOILERS AND APPARATUS TO BE USED ON BOARD OF STEAMBOATS TO PREVENTTHE EXPLOSION OF BOILERS.

Specification forming part of Letters Patent No. 1,122, dated April 15,1839; Reissued November 23, 1852.

To all whom it may concern Be it known that I, CADWALLADER EVANS, of thecity of Pittsburgh, in the county of Allegheny, in the State ofPennsylvania, have invented certain new and useful Im proveinents inSteam-Boilers and Steamboats for the Purpose of Preventing the Explosionof Boilers; and I do hereby declare that the following is a full andexact description thereof.

The apparatus which I employ for the purpose of preventing exploslonsconsists of several distinct devices intended to meet the variouscircumstances which are believed to be the causes of such explosions. Apart of them may be omitted on board of certain steamboats, but in suchas are used 111 our great western waters, it is believed that the wholeof them will be required to insure safety.

I use the ordinary safety valve on my boilers, but I combine therewithan apparatus intended to open the said valve when the temperature of theinterior of the boller is greater than is deemed compatible with perfectsafety and this I accomplish by a new mode of using the mixture ofmetals known as the fusible alloy, the fusion of which Wlll cause thesafety valve to open although the pressure of the steam may not be suchas to produce that effect.

Figure 1 in the accompanying drawing represents a longitudinal sectionof a cylindrical boiler, A being the common safety valve, resting on itsseat, and held down by the weight B. The lever O, of this safety valveis extended out beyond the standard which supports it, and enters arecess or opening cut away in the weight D, and which will allow thelever C, to descend should the safety valve be opened in the ordinaryway, by the pressure of the steam. The weight D, is supported on a rod,or stem, which enters a brass tube, or box E, containing the fusiblealloy, upon the surface of which the foot of the stem rests. The tube orbox IE, may extend to the depth of five or six inches, or, if preferred,as low as to the upper sides of the fines, as shown by the dotted lines.It will be seen that the necessary result of this arrangement will bethe opening of the safety valve by the pressure of the weight D, uponthe melting of the fusible alloy.

A very general source of steam boiler explosions is the absolute orrelative deficiency of water within them; the relative deficiency arisesgenerally from careening, by which, when there are several boilers, sidebyside, operating conjointly, there will be an excess of water in thelower boilers, and a corresponding deficiency in the upper ones,although the whole quantity, if properly distributed, may be the properamount.

To render the fact of the absolute or relative deficiency of water inthe boilers known not only to the engineer but to the passengers onboard of a steamboat, and to lead to the immediate correction of theevil, I employ an alarm apparatus, which by giving two diflerent anddistinctive sounds, will communicate the desired information.

I furnish the two outside boilers, in any series of boilers on board ofa steam boat with a float like that shown at F, Fig 1, which is to riseand fall by the rise'and fall of the water within the boiler. This floatis suspended by a lever G, G and may work on a fulcrum attached to thetube or box IE, or in any other convenient way. H, is a weight on theopposite end of the lever to form a suitable counterpoise to the float.A small valve a, the stem of which passes through a slot in the lever G,closes an opening in the tubular chamber 6, which leads to a horn 0,through which steam will escape should the valve a, be opened. When thefloat F, descends from a deficiency of water in the boiler, the lever G,will be brought into contact with the button 6, on the stem of the valveon, which will open said valve, and the steam escaping through the hornwill cause it to soundf, is a bow spring intended to keep the va ve a,up against its seat, when it is not depressed by the action of thefloat. To the similar apparatus on the opposite outside boiler, I attacha whistle instead of a horn, and when one or the other of theseinstruments gives a sound it will be known that the water in the boilerfrom which it proceeds, has descended below the proper level.

Should the boat be in good trim, and there should be an absolutedeficiency of water in the boilers, the two instruments will sound at,or near, the same time, and the proper remedy will be at once indicated.Should the sound be produced in consequence of the heeling of the boatproducing a deficiency of water in the upper boiler, the passengers mayat once apply the proper remedy by moving toward that side of the boatfrom which the sound proceeds, and thus producing an equilibrium. Byuniformly placing the same instrument on the larboard and starboardsides of a boat, and by proper printed directions, conspicuously placed,this simple remedy will be readily understood, and as readily applied,by the passengers, who constitute the shifting ballast, and will thus beenabled to correct the evil which they not infrequently produce.

I sometimes use a similar apparatus 6 for blowing off steam, should thewater in the boiler be too high.

In order to render the indication of the float the more perfect Isurround it by an iron casing g, g, which will protect it from theagitation to which it might otherwise be subjected by the ebullition ofthe water in the boiler; the manner of forming this casing, by which itwill tend to prevent the agitation of the water from the cause abovenamed will be clearly seen in Fig. 2, which is a cross section of theboiler, g, g, being the iron casing, and h, h, fiues passing through theboiler. 1

Fig. 3, represents what I denominate a water level, which is to beplaced within the cabins of steamboats, and'which will, upon inspection,point out to the passengers, at all times, the exact trim of the boat,and will cooperate with the indications of the horn and whistle in thelast described apparatus, in making known the quantity of water in theboilers, and the deviation thereof from the proper level. In this figureH, H. H, are five boilers, shown in cross section, having fiues I, I, I,running through them. J, J, J, is a copper tube, about one inch indiameter, and long enough to extend from the center of one of theoutside boilers, to the center of the other. It runs along under thecabin floor, and turns up at right angles at each end, passing throughthe floor, and rising as at J, J, opens into glass tubes z, i, z, 71.These tubes are furnished with graduated scales j, The water which is tobe contained in the copper and glass tubes is intended to rise to suchheight as to reach the center dark line on each scale when the boat ison a perfect level. To render'the height of the water perfectlyconspicuous, small light balls 7s, 70, which may be colored black, areallowed to float upon its surface. This water level is sustained bystandards Z, Z, Z, resting on the tops of the boilers, and has nosupport whatever from the wood work of the vessel, as the parallelism ofthe line which joins j, j, the center lines of the scale, with the truewater line m, m, must be always preserved, or the indications'of thewater level would be inaccurate. This water level will be found to be amost important auxiliary to the other means adopted by me for theprevention of explosions, as by its aid the relative height of water inthe respective boilers is at all times clearly shown, and with theassistance of the horn and the whistle, its absolute height can also bedetermined with perfect accuracy. By observing the floating balls in theglass tube, at the time of the sounding of the horn, or of the whistle,should they be found to stand nearly on a level, it would be manifestthat the water in the boilers was nearly as low as was consistent withsafety while the boat was on an even keel; should the horn and thewhistle both sound it would show that the water was at such a heightonly as sufficed merely to cover the flues, and that a fresh supply wasimmediately required. "When the boat is out of level, and one of theinstruments begins to sound, the difference in the height of the twoballs will be equal to the absolute height of the water in the lowerboiler above that in the upper; and as the escape of steam through thehorn or whistle takes place at a known point, the absolute height of thewater in the boilers when the boat is again put in trim, willnecessarily be known.

In Fig. 2, and also in Fig. 4, is represented my arrangement of theapparatus 'for causing a stream of water to enter the.

furnace, and extinguish or deaden the fire, whenever the temperaturerises so high as to melt the fusible alloy.

K, is a cold water cistern, to be filled by a suitable pump, and fromwhich the boilers may occasionally be supplied with water.

L, is a tube leading from this cistern into the furnace. This tube has avalve 72, adapted to its upper end, which valve would be raised by thedescent of the end 0, of the lever to which the valve rod is attached.The weight M, is sustained by its bearing upon the fusible alloycontained in a suitable box, in the manner already described, and shouldthis fuse the lever 0, will necessarily be forced down, and the waterwill flow into the fire.

It is a well known fact that a very large proportion of the explosionsof steamboat boilers have occurred immediately after leaving a landingplace, and this, in most instances, it has been admitted has arisen fromthe effect of the careening of the boat, by the assembling of thepassengers on one side thereof, or from other circumstances; thiscareening necessarily produces a diminution of water in the raised, andan excess in the depressed boilers, the sudden return of which causesthe explosion. The apparatus represented in Fig. 4 is intended to guardagainst this accident.

N, N, is a strong upright piece of timber which is made to slide up anddown by means of a rack and pinion, operated by suitable gearing. Thesliding timber is retained in its proper position by passing throughmortises, or guide pieces, and may be readily forced down when the boatis at a landing, so that its lower end bearing upon the bottom of theriver will effectually prevent the ca-reening of the boat, and thusdisastrous consequences resulting there from.

Having thus fully described the manner of constructing the variousdevices invented and applied by me for the purpose of pre venting theexplosion of steam boilers, and pointed out the manner in which theyoperate, I claim as my invention, and desire to secure by LettersPatent,

1. The manner in which I have combined and connected the common safetyvalve with the apparatus which is to operate by the melting of thefusible alloy, this apparatus, being constructed, and operating,substantially in the manner set forth; by which arrangement the safetyvalve is left free to be opened by the pressure of steam, in theordinary way, while it will also be opened by the safety apparatus fromthe influence of temperature alone independent of pressure from theelasticity of the steam. I lay no claim to the use of the fusible alloyto allow the escape of steam, but only to the combination in which Ihave used it, as set forth.

2. I claim the manner in which I have combined the float with the valveswhich it is intended to open in the outside boilers of any series, so asto cause a horn to sound on one side, and a whistle on the other, or byits escape to produce two different distinctive and characteristicsounds, which shall give information when the water has descended oneither side to a point as low as it can be safely allowed to descend. I

do not claim the causing of a horn, whistle, or other instrument, tosound from the escape of steam, but only the combination and arrangementof the parts as described, so as to afford the desired information inthe manner set forth.

I claim the manner in which I have arranged the water level, or levelwhose indications are governed by any other fluid, adapted to thepurpose, by which arrangement and combination as set forth, that is tosay, the water level resting on the boilers independently of the woodwork of the boat, and extending up into the cabin, where it is made toshow the level of the water in the boilers, by the cooperation of theapparatus last described, namely the apparatus for sounding a horn or awhistle, and affording by this conjoint action, a knowledge of theheight of water in the boilers respectively. I do not claim the waterlevel alone,

but only as arranged and combined by me,

as described.

4. I claim the particular apparatus for extinguishing the fire, asherein set forth, operating by means of the fusible alloy apparatus,substantially as described.

5. And lastly, I claim the arrangement and application of the apparatusfor preventing the careening of a steamboat at a wharf, pier, landing,or other stopping place. I do not claim the giving motion to a verticaltimber, or to a sliding apparatus by means of a rack and pinion gearing,this being a well known device, but confine my claim in this particularcase, to the combining and employing of this apparatus, with asteamboat, by which a new and important result is attained.

C'ADWALLAD'ER EVANS.

Witnesses TI-IOS. P. Jonas, ALoNzo G. HULL.

[FIRST PRINTED 1914.]

